By Leah Crane
Alexander W Helin/Getty Images
Robots made with rat spines could be used to study diseases as they progress through tissues, and may eventually lead to biological prosthetics.
Collin Kaufman at the University of Illinois at Urbana-Champaign and his colleagues built biological robots using 3D-printed muscles made of lab-grown mouse cells. But on their own, the muscles can’t do much – they need some sort of way to control them.
Instead of attaching the muscles to some sort of electrical control system, the researchers used the part of a rat spine that controls the hind legs. When they attached the spine to the muscle, the spine extended neurons into the muscle and began sending electrical signals through them that made the muscle contract.
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The spine and muscle were connected to a flexible scaffold with two arms sticking out perpendicular to the spine, so that when the muscle contracted the scaffold flexed and the arms pointed towards one another.
“The spinal cord is able to recognize these muscles and do what it does in the body – create these rhythmic contractions – after being out of the body for more than a week,” says Kaufman. The contractions could be controlled by adding or removing neurotransmitters from the system.
These spinal neurons, which make up the peripheral nervous system, are notoriously difficult to study in live animals, making it hard to understand diseases that affect them such as amyotrophic lateral sclerosis (ALS), also known as motor neurone disease. Systems like this could make it easier to study the progression of those diseases in real time, Kaufman says.
This robot is only about 6 millimetres long, and making them larger is a challenge because of the difficulty of getting nutrients to all of the tissue. But once we develop a way to make them bigger, they could have other medical uses.
“Eventually, something like this could be used for prosthetics,” says Kaufman. But that would probably be done using lab-grown human tissues, not rat spines, he says. “Nobody will have scary rat-spine hands.”
Journal reference: AIP Bioengineering, DOI: 10.1063/1.5121440
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